Electronic devices may be subject to counterfeiting by, for example, substituting an original component with a separately manufactured but subverted “look-alike” after the device has been certified by the manufacturer. If the counterfeit component remains undetected, a device having this counterfeit component contained therein is vulnerable. For example, the counterfeit component may perform the same functions as the intended component but may also contain additional functions that can be triggered by an adversary to compromise the security of the device or systems connected thereto.
A protection scheme may be utilized to detect these counterfeit components. Examples of protection schemes include using a key as a digital identifier to authenticate the source of the component. However, because such keys may be stored in memory, this digital identifier may be circumvented by reading the key from the memory, for example, with optical methods or the like.
In contrast, Physically Unclonable Function (PUF) technology, exploits manufacturing variations to derive a digital identifier. Because the digital identifier is hidden in the form of unique physical analog identifiers within the hardware, the digital identifier is not stored in binary form when the chip is powered down, and therefore, the key may not be stored in a memory that can be read. Further, because the PUF depends on random process variation, it is very difficult for a counterfeiter to create a counterfeit component having a same PUF as an original component. Therefore, it may be advantageous to use utilize a PUF as an identifier of a component.
However, when the key is initially generated from the PUF and when the PUF is regenerated again to determine the key for authentication, analog signals are generated based on physical proprieties of the device and subsequently digitized to generate the PUF. Noises in these analog measurements may make it difficult to determine the PUF, and, thus it may be difficult to authenticate the component. For example, if the analog measurement lies near a quantization boundary used to digitize the analog measurement, noise present during one of the generation and authentication phases of the PUF can flip the digitized value resulting in a key mismatch. Therefore, it may be desirable to utilize an error correction scheme with a PUF. However, conventionally, such error correction schemes may leak information about the PUF, which may compromise the integrity of the PUF.